Components in computer systems generally communicate over a bus. While at one time systems had only one bus, multiple bus architectures operating within multiple processor system environments have become more common. As a result, bus interfaces or bridges are needed between two buses to facilitate the transfer of data from one bus to another.
In some programming applications, it is desired that the bus interface only pass certain addresses on to target devices and ignore other addresses. Some systems for accomplishing this result can be unduly complex. It would thus be advantageous to have a simple and easily implemented system for providing an indication as to which addresses should be passed on to targets.